Breast pumps are known and are used for aspirating and storing mother's milk, so that a baby can also be fed with natural mother's milk when its mother is absent. Such devices have a funnel-shaped breast body, which is connected via a suction body and a suction line with a manually or electrically operated suction pump.
A manually and motor-driven breast pump is described in U.S. Pat. No. 5,007,899, wherein the partial vacuum can be manually preselected in three stages by means of a switch disposed on the pump unit. Holes are provided for this in the pump cylinder, through which the amount of leakage air can be regulated, depending on whether one or two holes are opened for leakage air. In connection with this device it is disadvantageous that the partial vacuum cannot be set continuously adjustable and that the pump unit provided for this must have a large structure.
A battery-operated breast pump is described in U.S. Pat. No. 4,964,851, wherein the pump is placed directly on the aspirating unit. For regulating the partial vacuum a screw device is provided on the pump body which, by means of a rotary movement over several connected components, finally exerts a force on a spring which regulates the air intake. By means of this it is possible to obtain a continuous and continuously adjustable regulation of the partial vacuum. The complicated structure of this pressure regulation of this device is disadvantageous. In addition, handling has been shown to be unfavorable because of the accessibility of the screw device of the pressure regulator on the one hand, and on the other hand because it is necessary to move the pump unit together with the entire aspirating device.
Although breast pumps have been proven, they have the disadvantage that the partial vacuum generated in a vacuum chamber of the suction body, which is transmitted over the breast when the breast body has been applied, is solely determined by the output of the suction pump and cannot be changed at all or only in an unsatisfactory manner. Thus, with too low a partial vacuum the aspiration of the milk can be slow and inefficient, while it can be unpleasant and painful with too high a partial vacuum.